流动式起重机卷筒直径与钢丝绳直径比值不小于16；滑轮直径与钢丝绳直径比值不小于18。（）
参考答案：对
Our principal the visitors our school.
A．shows;to
B．show; for
C．showing; in
D．shows; around
牛的选配原则。
